If you're the type who follows the sales of classic rock instruments, it should come as no surprise to learn that Indianapolis Colts owner Jim Irsay bought two of the guitars that Pink Floyd's David Gilmour auctioned off last week. In a new interview, he explained why he spent slightly more than $5 million, including $3.975 million for the famous "Black Strat, a 1969 Fender Stratocaster that Gilmour used on nearly every recording between 1973 and 1983.

“I just fucking love Pink Floyd, man, I cannot deny it,” Irsay told Rolling Stone. “I think [Roger] Waters’ lyrics and Gilmour’s playing and their whole story and prominence is just so profound that I cannot say enough about my excitement for this. … David Gilmour stands by himself.”

In addition to the Stratocaster, which set a record for an electric guitar sold at an auction, Irsay paid $175,000 for the guitar's flight case and $1.095 million for the 1969 Martin D-35 acoustic (a record for a Martin) on which Gilmour has written many songs. The auction, in which 127 instruments were sold, raised $21,490,750 for ClientEarth, an organization that funds lawyers who are fighting climate change.

“It is so soothing that someone from rock & roll would want to participate right in the center aspect of helping planet Earth,” Irsay said. “God knows we need it. It’s a very serious topic, so I think it’s a wonderful thing. And very seldom do you see the likes of literally $20 million raised for something like it. That is significant capital towards a cause.”

Irsay, who remembered seeing Gilmour play the Black Strat in concert in 1977, added that after he bought the case, he felt obliged to spend whatever it took to get the guitar for which is was built.

“If I don’t get the guitar, I’ll look like a jackass,” he said. “But I love Strats, and this is the Strat. This is the one that was the signature guitar for those incredible Floyd leads.”